Requirements for input/output (I/O) pin connections between circuit cards and motherboards often exceed the available circuit card edge length and exceed the maximum available connector pin density. One solution to this problem is the use of a supplemental card portion called a “mezzanine” card (sometimes referred to as a “daughter” card) that is mounted to the main circuit card (referred to generically as the carrier card) in order to provide one or more additional connectors and additional I/O pins. Such mezzanine cards are useful to provide additional functionality to a main circuit card, typically in the form of increased I/O capability. This increased I/O capability serves a variety of applications such as data acquisition and communication just to name a few. Mezzanine cards provide a convenience for configuring a carrier card. For a given carrier card with a suitable Field Programmable Gate Array (FPGA), there can be numerous configurations of attachable mezzanine cards that can satisfy a wide application scope. Modules can be digital, analog, communication, etc. and there can be a “mix” of such modules on a single carrier card. As applications continue to demand increased data processing and communications, while retaining compact physical size, mezzanine cards are commonly used to meet these demands.
However, the use of mezzanine cards creates new design issues because the connectors on the main circuit card and the mezzanine card must be spaced at a carefully controlled distance so that the circuit card and mezzanine card connectors can be mated properly with the mating connectors that are positioned on the main circuit card. The spacing between the connectors on the main circuit card and the mezzanine card is relatively small. Since electronic devices on the mezzanine card give off heat during operation, the confined area between the main circuit card and the mezzanine card also makes heat dissipation an issue. Furthermore, since the applications for which the mezzanine cards are used often are harsh environments with considerable mechanical vibration, there is also an issue regarding the robustness of the mechanical mounting of the mezzanine card to the main circuit card. Therefore, it is desirable to have an improved mezzanine structure for PC assemblies.